ENVIRONMENT AND REGENERATION 



503 



GENERAL DISCUSSION 



In comparing the effects upon metabolism of abnormal hy- 

 drogen ion concentrations, low Oxygen, and low temperature, 

 it is of interest to note that alike they cause decrease in both 

 the rate of regeneration and the total amount regenerated. Were 

 the effects of these agents due wholly to their action in retarding 

 the metabolism and consequent division and growth of the cells 

 of the regenerating parts, the result would not be a decrease in 

 the total amount ultimately regenerated, but rather an increase 



TABLE 8 

 Effect of temperature on regeneration 



' T" = transferred to temperature 18° to 21°C. 



in the length of time necessary to complete regeneration. This, 

 however, is not the case, for in acids and bases the tadpoles in 

 the higher and more detrimental concentrations cease regener- 

 ating at a time as early or earlier than the controls. In low 

 oxygen regeneration ceases at practically the same time in all 

 concentrations, while in low temperatures, although the period 

 of growth is longer at the lower than at the higher temperatures, 

 the difference is not sufficient to compensate the difference in 

 rate of regeneration, so that the ultimate amount regenerated 

 is still less at the lower than at the higher temperatures. 



